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| Question 531815:  Find the vertex and focus of a parabola with the given equation.
 y2-6y-12x+21=0
 and also this equation
 x2+4x-8y-4=0
 Answer by lwsshak3(11628)
      (Show Source): 
You can put this solution on YOUR website! Find the vertex and focus of a parabola with the given equation. y2-6y-12x+21=0
 and also this equation
 x2+4x-8y-4=0
 **
 y2-6y-12x+21=0
 complete the square
 (y^2-6y+9)=12x-21+9=12x-12=12(x-1)
 (y-3)^2=12(x-1)
 This is an equation of a parabola of standard form: (y-k)^2=4p(x-h), with (h,k) being the (x,y) coordinates of the vertex. Parabola opens rightwards.
 For given equation:
 vertex: (1,3)
 4p=12
 p=3
 focus: (1+p,3)=(4,3) (p units from vertex on axis of symmetry)
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